The ideal ARM platform for a next-generation Nitrogen Logic controller would feature a fast CPU, a GPU with included drivers, reliable USB port(s), and gigabit Ethernet, ideally for ~$100 or less.  A GPU would allow implementation of features like data smoothing, rotatable zones, custom shaped zones, and more.

The SheevaPlug has a fast enough CPU, excellent USB support, and gigabit Ethernet, but no GPU.

The D2Plug includes a GPU (with unknown driver availability), but costs too much.

The older Beagleboard had good enough USB support, but the USB bus sometimes died on Rev.C3 boards, it has no network interface, a slower CPU, difficult GPU drivers, and a higher price than the SheevaPlug.

The Raspberry Pi has a slower CPU, but a good GPU and a great price.  Unfortunately it only has 100mbit Ethernet attached via USB and terrible USB support (can't even get a single coherent frame from the Kinect).

The Odroid-X has loads of CPU power and a reasonable price for what it provides, but USB-based 100mbit Ethernet.

The BeagleBone looks promising, but I wasn't able to find GPU drivers as easily as for the PandaBoard or Raspberry Pi.  It also requires a separate power supply.

It seems the platforms with good I/O (e.g. the Marvell platforms with gigabit Ethernet, good USB support, eSATA, and even PCI express) either lack GPUs or are priced too high, and the platforms with good GPUs lack drivers and satisfactory I/O (e.g. Raspberry Pi).  Someone please make a low-cost ARM system with real (not USB-connected) Ethernet, solid USB 2.0 or 3.0 support, an enclosure, and a GPU with easily accessible drivers!